Synthesis of CoFe Prussian blue analogue/poly vinylidene fluoride nanocomposite material with improved thermal stability and ferroelectric properties

2018 ◽  
Vol 42 (6) ◽  
pp. 4567-4578 ◽  
Author(s):  
Pramod Bhatt ◽  
Sher Singh Meena ◽  
M. D. Mukadam ◽  
Balaji P. Mandal ◽  
A. K. Chauhan ◽  
...  

Synthesis of a nanocomposite CoFe Prussian blue analogue (CoFePBA) molecular magnet with a polyvinylidene fluoride (PVDF) polymer show improved thermal stability and ferroelectric properties.

Author(s):  
Alexander A. Pud ◽  
◽  
Nikolay A. Ogurtsov ◽  
Olga S. Kruglyak ◽  
◽  
...  

The work is devoted to the development and study of conducting nanocomposites of poly(3-methylthiophene) (P3MT) and poly(vinylidene fluoride) (PVDF), suitable for changing properties when interaction with of the environment components, and to find factors of influence on properties of such materials. The kinetic aspects of P3MT formation in the process of 3-methylthiophene (3MT) polymerization in PVDF dispersions in the presence of dopants of different nature, in particular, chloride (Cl-), as well as surface-active dodecylbenzenesulfonate (DBS-) and perfluorooctanoate (PFO-) anions are studied. It is found that DBS- and PFO- anions inhibit 3MT oxidation and decrease P3MT yield in comparison with those of chloride anions. It is shown that P3MT is formed through two consecutive kinetically different reactions of pseudo-first order in terms of the oxidant concentration. Transmission electron microscopy revealed that as a result of such polymerization nanoparticles of doped P3MT formed a surface inhomogeneous layer on PVDF particles, thus forming nanocomposite particles with core-shell morphology. Thermal studies showed higher thermal stability of the doped P3MT phase in the nanocomposite compared to the pure polymer. It is found that thermal stability of the P3MT phase in the PVDF/P3MT-DBS nanocomposites is higher than in the PVDF/P3MT-Cl. The influence of the dopant nature and content of doped P3MT on conductivity and sensitivity of the nanocomposites to vapors of harmful volatile organic compounds (acetone and isopropanol) is characterized. The strongest responses to acetone are shown by the nanocomposite with PFO- dopant. In the DBS- dopant case medium intensity responses are found and the lowest ones are observed for Cl- dopant. It is shown that the sensitivity of nanocomposites extremely depends on the conducting polymer content.


Author(s):  
Guanchun Rui ◽  
Yanfei Huang ◽  
Xinyue Chen ◽  
Ruipeng Li ◽  
Dingrui Wang ◽  
...  

Oriented amorphous fraction in biaxially oriented poly(vinylidene fluoride) gives it significantly enhanced dielectric and ferroelectric properties.


Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3265 ◽  
Author(s):  
Li ◽  
Li ◽  
Li ◽  
Guan ◽  
Zheng ◽  
...  

A new synthesis method for organic–inorganic hybrid Poly(vinylidene fluoride)-SiO2 cation-change membranes (CEMs) is proposed. This method involves mixing tetraethyl orthosilicate (TEOS) and 3-mercapto-propyl-triethoxy-silane (MPTES) into a polyvinylidene fluoride (PVDF) sol-gel solution. The resulting slurry was used to prepare films, which were immersed in 0.01 M HCl, which caused hydrolysis and polycondensation between the MPTES and TEOS. The resulting Si-O-Si polymers chains intertwined and/or penetrated the PVDF skeleton, significantly improving the mechanical strength of the resulting hybrid PVDF-SiO2 CEMs. The -SH functional groups of MPTES oxidized to-SO3H, which contributed to the excellent permeability of these CEMs. The surface morphology, hybrid structure, oxidative stability, and physicochemical properties (IEC, water uptake, membrane resistance, membrane potential, transport number, and selective permittivity) of the CEMs obtained in this work were characterized using scanning electron microscope and Fourier transform infrared spectroscopy, as well as electrochemical testing. Tests to analyze the oxidative stability, water uptake, membrane potential, and selective permeability were also performed. Our organic–inorganic hybrid PVDF-SiO2 CEMs demonstrated higher oxidative stability and lower resistance than commercial Ionsep-HC-C membranes with a hydrocarbon structure. Thus, the synthesis method described in this work is very promising for the production of very efficient CEMs. In addition, the physical and electrochemical properties of the PVDF-SiO2 CEMs are comparable to the Ionsep-HC-C membranes. The electrolysis of the concentrated CoCl2 solution performed using PVDF-SiO2-6 and Ionsep-HC-C CEMs showed that at the same current density, Co2+ production, and current efficiency of the PVDF-SiO2-6 CEM membrane were slightly higher than those obtained using the Ionsep-HC-C membrane. Therefore, our novel membrane might be suitable for the recovery of cobalt from concentrated CoCl2 solutions.


2001 ◽  
Vol 665 ◽  
Author(s):  
Feng Xia ◽  
H.S. Xu ◽  
Babak Razavi ◽  
Q. M. Zhang

ABSTRACTFerroelectric polymer thin films are attractive for a wide range of applications such as MEMS, IR sensors, and memory devices. We present the results of a recent investigation on the thickness dependence of the ferroelectric properties of poly(vinylidene fluoridetrifluoroethylene) copolymer spin cast films on electroded Si substrate. We show that as the film thickness is reduced, there exist two thickness regions. For films at thickness above 100 nm, the thickness dependence of the ferroelectric properties can be attributed to the interface effect. However, for thinner films, there is a large change in the ferroelectric properties such as the polarization level, the coercive field, and polarization switching speed, which is related to the large drop of the crystallinity in the ultrathin film region (below 100 nm). The results from Xray, dielectric measurement, and AFM all indicate that there is a threshold thickness at about 100 nm below which the crystallinity in the film reduces abruptly.


2008 ◽  
Vol 1071 ◽  
Author(s):  
Koji Aizawa

AbstractCharacterization of 700-nm-thick poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)]/TiO2/Al-doped ZnO (AZO) structures on a glass substrate were investigated. In this study, the sputtered TiO2 films as insulator were used for the reduction of leakage current. The leakage current density of the fabricated Pt/P(VDF/TrFE)/AZO and Pt/P(VDF/TrFE)/170-nm-thick TiO2/AZO structures were approximately 8.7 and 3.9 nA/cm2 at the applied voltage of 10 V, respectively. In the polarization vs. voltage characteristics, the fabricated Pt/P(VDF/TrFE)/TiO2/AZO structures showed hysteresis loops caused by ferroelectric polarization. The remnant polarization (2Pr) and coercive voltage (2Vc) measured from a saturated hysteresis loop at the frequency of 50 Hz were approximately 12 μC/cm2 and 105 V, respectively. These results suggest that the insertion of TiO2 film is available for reducing the gate leakage current without changing the ferroelectric properties.


2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660013
Author(s):  
Yammani Venkat Subba Rao ◽  
Aravinda Narayanan Raghavan ◽  
Meenakshi Viswanathan

The ability to create patterns of piezo responsive material on smooth substrate is an important method to develop efficient microfluidic mixers. This paper reports the fabrication of Poly vinylidene fluoride microfilms using spin-coating on smooth glass surface. The suitable crystalline phases, surface morphology and microstructural properties of the PVDF films have been investigated. We found that films of average thickness 10[Formula: see text][Formula: see text]m, had average roughness of 0.13[Formula: see text][Formula: see text]m. These PVDF films are useful in microfluidic mixer applications.


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